ABSTRACT
Exploiting the high peak intensities characteristic of short laser pulses to excite multiphoton processes or to drive highly nonlinear phenomena (and generate new wavelengths, for example), while maintaining the high resolution characteristic of CW sources to investigate very narrow spectral structures of atoms or molecules, is one of the forbidden dreams of the laser experimentalist. Unfortunately, the two conditions of short pulse duration and high spectral resolution normally appear in striking contrast, since short pulses invariably correspond to broad spectral bandwidths that limit the frequency resolution to the inverse of the pulse duration (see Figure 6.1a).
